Lasers are now commonly used for tactical designation, detection and ranging. Laser-based tactical systems can be used to detect many types of military vehicles, including submarines, ships, land vehicles and aircraft.
There are two types of laser-based systems. One type is “LIDAR,” which typically uses laser pulses and is fully analogous to RADAR. The other is “laser designation,” wherein the target is illuminated with a continuous beam or pulse train. LIDAR systems obtain range and bearing, while laser designating systems use reflected laser energy (possibly from a third platform) to home on the target.
FIG. 1 depicts a conventional scenario involving a target vehicle 122, which is moving in direction 124, and LIDAR system 120, which is capable of detecting and ranging the target vehicle. In operation, LIDAR system 120 emits a beam of laser light 126 having a specific wavelength λ1 (e.g., an infrared wavelength, etc.) toward target vehicle 122. When it impinges on target vehicle 122, the light is reflected to LIDAR system 120. A sensor in the LIDAR system detects reflected light 128 at wavelength λ1. Processing electronics within LIDAR system 120 ranges target vehicle 122 using, for example, the round-trip time of light beams 126 and 128.
In order to avoid detection or frustrate attempts at ranging by such systems, military vehicles often use “obscurants” to obscure their presence. But relatively few obscurants are effective against LIDAR or laser-designation systems. In fact, obscurants for these laser-based systems are typically limited to classical systems, such as smoke and water spray (for ships). And while somewhat effective for use by aircraft and land vehicles, smoke is generally not available for use as an obscurant for submarines.
Consequently, there is a need to develop new obscurants and a method to use them to bolster the limited arsenal of countermeasures available against LIDAR and laser-designation systems. And for obvious reasons, there is a continuing need to develop better “taggants” that tag vehicles to facilitate their detection and ranging.